Effect of surface mechanical attrition treatment (SMAT) on boronizing of EN8 steel

► SMAT promotes diffusion of boron and increases the case depth of a boronized layer. ► SMAT treated EN8 steel can be boronized with a reasonable case depth at 923 K for 7 h. ► Duplex treatment is beneficial to achieve a desired case depth and a dense boronized layer. ► SMAT promotes the formation of an FeB phase along with an Fe2B phase on EN8 steel. ► SMAT can be used as a pre-treatment for boronizing of steel.